Sheet guide apparatus

Abstract

A sheet guide apparatus comprises gripper devices for holding and transporting a printed sheet, an impression cylinder and a transfer cylinder for holding and transporting the printed sheet received from the gripper device, and a first guide device for guiding the printed sheet being transported. A front end portion of the first guide device is located upstream, in the flow direction of the printed sheet, from a transfer position, where the printed sheet is transferred from the gripper device to the impression cylinder, and the front end portion of the first guide device is also located near the transfer position. Suction holes opening in a front end portion of a plate-shaped guide of the first guide device are provided for sucking air. The sheet guide apparatus suppresses fluttering or instability of the sheet.

1. A sheet guide apparatus, comprising:
 transport means for holding and transporting a sheet;  
 a first transport cylinder for holding and transporting the sheet received from said transport means; and  
 a guide member for guiding the transported sheet, a first end portion of said guide member being located upstream, in a sheet transport direction, from a first transfer position where the sheet is transferred from said transport means to said first transport cylinder, said first end portion of said guide member being also located adjacent to said first transfer position, said guide member being provided with first suction holes opening at a tip of the first end portion for sucking air.  
 
   
   
     2. The sheet guide apparatus according to  claim 1 , wherein said guide member includes guide portions provided with spacing in a width direction of the sheet, and said tip of the first end portion includes ends of said guide portions. 
   
   
     3. The sheet guide apparatus according to  claim 2 , wherein
 said first transport cylinder includes holding means for holding the sheet,  
 said guide member includes a plate-shaped member extending in the width direction of the sheet and disposed adjacent said first transfer position, and  
 said spacing of said guide member is defined by notch portions provided in an end portion of said plate-shaped member facing said first transfer position, said notch portions corresponding to said holding means.  
 
   
   
     4. The sheet guide apparatus according to  claim 1 , further comprising:
 a second transport cylinder for transferring the sheet to said transport means; and  
 suction means for sucking air present between said second transport cylinder and the sheet located downstream of a second transfer position, in the sheet transport direction, where the sheet is transferred from said second transport cylinder to said transport means, said suction means having second suction holes at a position where said second suction holes are not closed by the transported sheet.  
 
   
   
     5. The sheet guide apparatus according to  claim 4 , wherein said second suction holes of said suction means are formed in a second end portion of said guide member, opposite to and at an upstream side of the first end portion in the sheet transport direction. 
   
   
     6. The sheet guide apparatus according to  claim 1 , further comprising:
 air discharge means for discharging air onto the sheet held on said first transport cylinder to suppress instability of the sheet.  
 
   
   
     7. The sheet guide apparatus according to  claim 6 , wherein said air discharge means includes first air discharge means for blowing air toward a circumferential surface of said first transport cylinder located downstream, in a sheet flow direction, from said first transfer position of the sheet, said blowing being performed in a direction nearly perpendicular to a printed surface or a coated surface of the sheet, and second air discharge means for blowing air in a direction opposite to the sheet flow direction. 
   
   
     8. The sheet guide apparatus according to  claim 6 , wherein said air discharge means has first air discharge means and second air discharge means connected to a discharge air source, and said second air discharge means includes a valve for establishing and cutting off supply of discharge air. 
   
   
     9. The sheet guide apparatus according to  claim 8 , wherein said second air discharge means ejects air when the sheet has a first thickness and stops ejecting air when the sheet has a second thickness smaller than the first thickness. 
   
   
     10. The sheet guide apparatus according to  claim 1 , wherein said guide member includes a guide plate provided with a plurality of air injection holes that inject air in a width direction of the sheet. 
   
   
     11. The sheet guide apparatus according to  claim 1 , wherein said transport means is a skeleton cylinder. 
   
   
     12. The sheet guide apparatus according to  claim 1 , wherein said first transport cylinder is an impression cylinder provided downstream of said transport means in the sheet transport direction.